free board
DESCRIPTION
FREEBOARD OF TYPE A AND TYPE B SHIPTRANSCRIPT
TYPE-’A’ SHIPTYPE-’A’ SHIP
LIQUID CARGOES ONLYLIQUID CARGOES ONLY
CARGO TANKS LOW PERMEABILITYCARGO TANKS LOW PERMEABILITY
SMALL DECK OPENINGS, WATERTIGHT STEEL COVERSSMALL DECK OPENINGS, WATERTIGHT STEEL COVERS
HIGH DEGREE OF SUB-DIVISIONHIGH DEGREE OF SUB-DIVISION
IF +150m MUST REMAIN AFLOAT AFTER FLOODING OF IF +150m MUST REMAIN AFLOAT AFTER FLOODING OF ANY SINGLE EMPTY COMPART’tANY SINGLE EMPTY COMPART’t
TYPE-’B’ SHIPTYPE-’B’ SHIP
ANY SHIP WHICH IS NOT A TYPE ‘A’ SHIPANY SHIP WHICH IS NOT A TYPE ‘A’ SHIP
HAS A GREATER FREEBOARD THAN TYPE ‘A’ SHIPHAS A GREATER FREEBOARD THAN TYPE ‘A’ SHIP
LESSER DEGREE OF SUB-DIVISIONLESSER DEGREE OF SUB-DIVISION
VULNERABLE IN HEAVY WEATHER TO FLOODINGVULNERABLE IN HEAVY WEATHER TO FLOODING
LARGE DECK OPENINGSLARGE DECK OPENINGS
TYPE- ‘B-60’ SHIPTYPE- ‘B-60’ SHIP
ANY TYPE ‘B’ SHIP OVER 100 m LONGANY TYPE ‘B’ SHIP OVER 100 m LONG
STEEL HATCH COVERS WEATHERTIGHTSTEEL HATCH COVERS WEATHERTIGHT
REMAIN AFLOAT AFTER FLOODING OF SINGLE REMAIN AFLOAT AFTER FLOODING OF SINGLE COMPARTMENT ( COMPARTMENT ( = 95% ) AT SUMMER DRAFT = 95% ) AT SUMMER DRAFT
FREEBOARD REDUCED BY 60% OF TABULAR ‘A’ ~ ‘B’FREEBOARD REDUCED BY 60% OF TABULAR ‘A’ ~ ‘B’
TYPE- ‘B-100’ SHIPTYPE- ‘B-100’ SHIP
ANY TYPE ‘B-60’ SHIP OVER 100 m LONGANY TYPE ‘B-60’ SHIP OVER 100 m LONG
STEEL HATCH COVERS WATERTIGHTSTEEL HATCH COVERS WATERTIGHT
ACCESS TO E.R. FROM DECK PROTECTED BY HOUSEACCESS TO E.R. FROM DECK PROTECTED BY HOUSE
OPEN RAILS NOT BULWARKS FOR 50%LOPEN RAILS NOT BULWARKS FOR 50%L
CREW ACCESS BY GANGWAY OR UNDER DECK PASSAGECREW ACCESS BY GANGWAY OR UNDER DECK PASSAGE
REMAIN AFLOAT AFTER FLOODING OF ANY TWO FORE & AFT ADJACENT REMAIN AFLOAT AFTER FLOODING OF ANY TWO FORE & AFT ADJACENT COMPARTMENTS ( COMPARTMENTS ( = 95% ) AT SUMMER DRAFT = 95% ) AT SUMMER DRAFT
FREEBOARD REDUCED BY 100% OF TABULAR ‘A’ ~ ‘B’FREEBOARD REDUCED BY 100% OF TABULAR ‘A’ ~ ‘B’
STATE OF EQUILIBRIUMSTATE OF EQUILIBRIUMFinal waterline MUST BE below any opening that Final waterline MUST BE below any opening that allows ‘progressive’ floodingallows ‘progressive’ flooding
Final GM at least 0.05m.Final GM at least 0.05m.
Max. GZ not less than 0.1m.Max. GZ not less than 0.1m.
Final angle of heel 15Final angle of heel 15 or less or less
Positive range at least 20Positive range at least 20
Ships over 150m in length - E.R. is classed as Ships over 150m in length - E.R. is classed as floodable compartment ( floodable compartment ( as 85% ) as 85% )
TABLE-’A’ TABLE-’B’
LENGTH F’BOARD
100m 1180 mm
110m 1240 mm
120m 1263 mm
130m 1299 mm
140m 1355 mm
150m 1379 mm
160m 1423 mm
170m 1569 mm
180m 1642 mm
LENGTH F’BOARD
100m 1380 mm
110m 1440 mm
120m 1463 mm
130m 1499 mm
140m 1555 mm
150m 1579 mm
160m 1628 mm
170m 1770 mm
180m 1850 mm
FREEBOARD ASSIGNMENT
1. TABULAR FREEBOARD FROM TABLE ‘A’ OR ‘B’a) B-60 / B-100 correction
b) Wooden Hatch correction
c) Flush Deck correction ( ≤ 100m in length )
d) Block Coefficient correction ( Cb > 68% )
2. BASIC FREEBOARDa) Depth correction
b) Deck line position
c) Superstructure / Trunk correction
d) Sheer correction
e) Bow height correction
3. SUMMER FREEBOARDa) Owners request ( increase only )
b) Other increase ( cargo doors / ports below F’board deck )
4. ASSIGNED FREEBOARD
WOODEN HATCH CORRECTION
TABULAR F’BOARD INCREASED if in ‘POSITION-1’
( POSITION-1 = ALL OF F’BOARD DECK, + 25% OF SUPERSTRUCTURE DECK )
FLUSH DECK CORRECTION
TABULAR F’BOARD INCREASED FOR TYPE-B SHIPS
IF ≤ 100m IN LENGTH AND
SUPERSTRUCTURE IS ≤ 35% OF SHIPS LENGTH
E.G. SHIPS LENGTH = 100m, SUPERSTRUCTURE = 35m
BLOCK COEFFICIENT CORRECTION
FREEBOARD INCREASED IF Cb = > 0.68 WHEN MEASURED
AT 85% OF SUMMER DRAFT
F’BOARD IS MULTIPLIED BY ( 0.68 + Cb ) ÷ 1.36
MOULDED DEPTH
85% OF MOULDED DEPTH
DEPTH CORRECTION
STANDARD DEPTH FOR FREEBOARD RULES = L ÷ 15
IF DEPTH MEASURED = MORE THAN L ÷ 15
FREEBOARD IS INCREASED
DEPTH CORRECTION
STANDARD DEPTH FOR FREEBOARD RULES = L ÷ 15
IF DEPTH MEASURED = LESS THAN L ÷ 15
FREEBOARD IS REDUCED, IF:
SUPERSTRUCTURE = 60% L AMIDSHIPS POSITION, OR
CONTINUOUS TRUNK FULL LENGTH
DECK LINE POSTION CORRECTION
FREEBOARD MUST BE CAPABLE OF VERTICAL MEASUREMENT
IF SHIP HAS ROUNDED GUNWHALE,
DECK LINE IS LOWERED THUS:
Corrected freeboard
SUPERSTRUCTURE CORRECTION
SHIPS WITH SUFFICIENT “STANDARD HEIGHT” SUPERSTRUCTURE, OR
SUFFICENT WATERTIGHT TRUNKING
FREEBOARD WILL BE REDUCED
SUPERSTRUCTURE CORRECTION
IF SUPERSTRUCTURE / TRUNKING IS NOT SUFFICIENT IN HEIGHT / %AGE L / OR WIDTH,
NO REDUCTION IN FREEBOARD
SHEER CORRECTION
GREATER THAN STANDARD SHEER
FREEBOARD IS REDUCED
SHEER CORRECTION
LESS THAN STANDARD SHEER
FREEBOARD IS INCREASED
NO REDUCTION FOR SHEER IF:
LESS THAN 20% L SUPERSTRUCTURE AMIDSHIPS
CORRECTION FOR ‘BOW HEIGHT’
MINIMUM BOW HEIGHT IS CALCULATED BY FORMULA
FORMULA IS DEPENDENT ON L AND Cb
IF THE BOW IS LESS THAN CALCULATED HEIGHT
FREEBOARD IS INCREASED